The invention herein described was made in the course or under a contract thereunder with the United States Air Force Systems Command.
The invention relates to the catalytic codimerization of norbornadiene, hereinafter referred to as NBD, and acrylic acid ester, hereinafter referred to as AAE. Particularly, the invention relates to the preparation of a codimer using a specified catalyst system.
The resulting codimer can be used as a precursor for a missile fuel. The codimer can be hydrolyzed to an acid which can be decarboxylated. The resulting decarboxylated hydrocarbon can be used as a missile fuel.
NBD is also known as bicyclo-(2.2.1) heptadiene-2,5. A method of preparation is disclosed in U.S. Pat. No. 2,875,256 issued Feb. 24, 1959. The NBD can be represented by either one of the following structural formulas: ##STR1## NBD can be easily dimerized to a exo-exo hexacyclic dimer. Thus one problem in reacting NBD with another hydrocarbon reactant is to minimize the formation of the foregoing dimer while encouraging the formation of the desired codimer.
In the Journal of the American Chemical Society/97:4/Feb. 19, 1975, pages 812 & ff., R. Noyori et al in an article titled "Nickel (0)-Catalyzed Reaction of Quadricyclane with Electron-Deficient Olefins" discloses the reaction of alkyl acrylate and NBD using bis(acrylonitrile)nickel (0). With methyl acrylate the resulting product has the following structure. ##STR2## The reaction was run at various temperatures for a substantial amount of time. Yet the yield of codimer II was very low.
Thus, as the aforementioned article indicates, the specific synthesis problem is to obtain codimer III (which structure is defined herein) in both a high conversion and selectivity and with a rapid reaction rate.